We expect a query on structured data like dates and prices to return only
documents that match exactly. However, good full-text search shouldn’t have the
same restriction. Instead, we can widen the net to include words that may
match, but use the relevance score to push the better matches to the top
of the result set.

If documents exist that do contain exactly what the user has queried,
they should appear at the top of the result set, but weaker matches can be
included further down the list. If no documents match exactly, at least we
can show the user potential matches; they may even be what the user
originally intended!